1. Field of the Invention
The present invention relates to an image processing apparatus and image processing method for printing using a plurality of color materials.
2. Description of the Related Art
The following technique has been proposed to improve light resistance when both dye ink and pigment ink are used, and suppress color unevenness and gloss unevenness when pigment ink is used. The ink fixing order is controlled when, for example, so-called multi-pass printing is performed to form an image by printing a plurality of times in the same region on a printing medium (for example, Japanese Patent Laid-Open No. 2010-100017). That is, when both dye ink and pigment ink are used, it is controlled to always print the pigment ink higher in light resistance as an upper layer. When pigment inks of different colors are used, it is controlled to always print one color as an upper layer.
However, according to the ink fixing order control method disclosed in Japanese Patent Laid-Open No. 2010-100017, dots corresponding to each scan are thinned out in accordance with a given fixed pattern in multi-pass printing. This may impair the dispersibility of a dot pattern itself corresponding to each scan. Poor dispersibility of the dot pattern may locally disturb the once-controlled upper layer/lower layer relationship between inks owing to misregistration between printing scans and the interaction between inks.